Security is an important requirement in many document printing applications. In situations such as official or government document printing, event ticket printing, financial instrument printing and the like, many printed documents must be protected against copying, forging and/or counterfeiting.
One example of such a document is a prescription for medication. Upon receipt of a printed prescription, the pharmacist would like to have a good level of confidence that the document is genuine and is being used only once, by the person to which the prescription was issued. In applications such as this it is important that the document have a security feature that is difficult or impossible to copy, so that a single, valid, original prescription document is not used to create counterfeit copies that also contain the security feature. A security mark that does not survive reproduction is commonly called “fragile.”
Another example document is a confidential company customer list. In this situation, the document's creator may be concerned about the document falling into unauthorized hands and being altered. Thus, in a situation such as this, it is important that the security mark survive reproduction and distribution so that the document can tracked and/or the security mark decoded. A mark that does survive reproduction is commonly called “robust.”
For these reasons, many documents have multiple security elements, some of which are fragile and others of which are robust. This can require a substantial amount of document space to be dedicated to the security marks, as two marks typically require twice the space as one mark requires. In addition, many existing marks can be easily “cracked” (i.e., decoded by unauthorized users). To guard against this, many security printing processes require special materials, which typically increases printing costs.
This document describes methods and systems for creating and using a security mark that addresses at least some of the problems described above, and/or other problems.